Subject: Re: Requirements

From: "Khosravi, Hormuzd M" <[email-masked]>
Date: Mon, 22 Sep 2003 22:50:52 -0700

Hi Joel

I understand your concern regarding the architectural requirement (sec
5, #10) and I think we could clarify the text there, if still
possible...or may be use the Framework draft to clarify this? Lily, any
ideas?
However, I believe that the protocol requirement text is fine and it
should remain. From what I have heard so far, you agree that a) all FEs
have this info, b) some FEs might acquire this thru some inter-FE
discovery protocol or via FE manager and they should not be precluded
from ForCES, c) CE needs this info. If you agree with a, b & c then it
is natural to have some protocol mechanism to support this (whether it
is a general or special mechanism is a separate issue)...unless you want
to have a non-standard way to do this, which defeats the purpose of
ForCES. You have also agreed that it is ok to have some optional
mechanism for this. Now if you were in the Requirements team, which
unfortunately you were not :), would you rather define optional
requirements or mandatory ones ? This has a direct impact on the
protocol design and interoperability.

Also, I don't remember there having been any arguments or big
discussions around this requirement before atleast in the design team.
The only feeback we had received was from the IESG was to clarify the
text in the Protocol Req section 7, which we did. 

I hope you will understand my point of view.
Thanks a lot
Hormuzd

-----Original Message-----
From: Forwarding and Control Element Separation
[mailto:[email-masked]] On Behalf Of Joel M. Halpern
Sent: Saturday, September 20, 2003 5:57 PM
To: [email-masked]
Subject: Re: [FORCES] Requirements

A large part of my problem with this requirement is that it leads
sensible
implementors (such as yourself) to think that they need special protocol
mechanisms to support this.  It also leads sensible FE implementors to
think that they are somehow required to provide this implementation.

1) FE's better not be required to provide inter-FE topology information.

2) Allowing FEs which have such information to provide it does not
require
special protocol mechanisms in any reasonably designed protocol.  CEs
will
need to ask FEs for many pieces of FE level information.  If we must
have a
requirement in this area at all, it should be a requirement that the set
of
FE information a CE can query should include support for optional
information about inter-FE connectivity.  (A CE should not be required
to
ask about this, an FE should not be required to provide this, and it
really
should not be treated as special information requiring special protocol
support mechanisms.

Another way of looking at this is that there are many kinds of
information
that an FE might be able to provide that might or might not be
communicable
in the initial set of information mandated for CE-FE querying.  For lots
of
reasons, the protocol MUST be extensible.  Making support of this
information important relative to selecting / defining the protocol
seems a
serious mistake.

Yours,
Joel M. Halpern

At 05:35 PM 9/20/2003 -0700, you wrote:
>The text for this requirement has always been inter-FE topology (since
>v-02).
>I am pretty sure but I'll check with Todd anyways on this.
>
>If we do not provide protocol mechanisms to support this, then there
>will
>have to be non-standard ways to obtain this information from the FEs
>which
>provide this info, which we would like to avoid.
>
>Thanks
>Hormuzd